Summary

Peer-to-Peer (P2P) file-sharing has become the killer application in the Internet with respect to traffic and popularity which is even surpassing web usage. This makes P2P file-sharing commercially attractive to network operators interested in increased traffic. In parallel, the demand for wireless services has caused wireless networks to grow enormously. We assume that P2P file-sharing will be mapped onto mobile environments by its users. This results in a mobile P2P file-sharing service. In this project, we examined the feasibility of the eDonkey file-sharing service in GPRS and UMTS networks and detected problems of the interaction between P2P and infrastructure-based mobile networks. We developed an architecture overcoming the restrictions of today's existing P2P concepts and mobile networks. Additional infrastructure elements have been introduced which are operator friendly and permit the network operators to regulate the service while preserving the user friendly P2P characteristics. The performance capabilities of the architecture were evaluated by extensive analytical and simulative studies.

Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. In [1], we have investigated the performance of a crawling peer by means of simulations. Now, we show a time-discrete analysis of the crawling peer’s performance in order to investigate different scenarios and to enable parameter-sensitivity studies for further improvements of the crawling peer’s strategy.

Peer-to-Peer (P2P) file-sharing has become a major application in the Internet with respect to traffic volume which is even surpassing web usage. This characteristic makes P2P commercially attractive to network operators interested in increased traffic. In parallel, the demand for wireless services has caused wireless networks to grow enormously. We assume that P2P file-sharing will be mapped onto mobile environments by its users. This results in a mobile P2P file-sharing service, which we denote as mobile P2P. In this paper, we examine the feasibility of the eDonkey file-sharing service in GPRS networks, detect problems of the interaction between P2P and the mobile network, and find solutions to overcome them. Furthermore, this paper measures and analyzes the characteristics of mobile P2P and gives first empirical performance values. Summarizing, the goal is the analysis of feasibility for an Internet-based filesharing application in a mobile network and to provide first measurements from two real-world networks.

Peer-to-Peer (P2P) file-sharing has become the killer application in the wired Internet and might also be highly attractive for mobile networks. In particular since UMTS operators are searching for new applications which do both: a) exploit the potential of the UMTS technology and b) motivate the user to adopt the new technology. Mobile networks differ from wireline networks mainly by the limited capacity of the radio link, the mobility of the users, and the anticipated content exchanged in these networks. P2P networks, in contrast, are overlays which run on top of a transport network. They consider the transport network only in an abstract way. P2P performance is typically considered on overlay level only. In a mobile environment, the question arises, whether the abstraction can be maintained for underlying mobile transport networks, too, and whether there will be a performance impact. In this paper we investigate the performance of a multiple source download mechanism as used in the popular eDonkey file-sharing network. The performance of the proposed mobile P2P architecture has already been considered for several factors, like the capacity of the mobile access network, the mobility of the users, the application of the cache peer, and the size of typical contents of mobile users such as ring tones, images, and mp3 audio files. However, the performance may be increased by adapting the size of the swapping entities in dependence on these main influence factors. The swapping entities are the smallest units for uploading and downloading user data and are called chunks and blocks, respectively. In this work, we show if and how the swapping entities influence the entire system.

P2P file sharing systems account for a high percentage of the traffic volume in the fixed Internet, having exceeded http (WWW) or email traffic [1] [2]. The increasing availability of mobile data networks such as GPRS and UMTS in conjunction with attractive pricing schemes makes P2P file sharing an interesting application also in the mobile context. But the operation of P2P systems in mobile environments encounters several problems, such as a relatively narrow and expensive air interface, highly varying online states (presence) of the subscribers, a hierarchical network structure (GPRS), and limited device capabilities. P2P is a distributed application architecture where equal entities, denoted as peers, voluntarily share resources, e.g. files or CPU cycles, via direct, end-to-end exchanges. In order to share resources, P2P applications need to support two fundamental coordination and control functions: Resource mediation mechanisms, i.e. functions to locate resources or entities, and resource control mechanisms, i.e. functions to permit, prioritize, and schedule the access to resources. Pure P2P architectures are implementing both mechanisms in a fully decentralized manner [3], while Hybrid P2P systems utilize central entities that collect mediation data. An example for a Hybrid P2P system is the eDonkey filesharing protocol, where the index servers collect and distribute file location information about all peers. The desire of mobile network operators is to add value to the P2P data flows and to turn P2P into a service they can charge for. When creating such services operators retain control on traffic and content. However the basic P2P user experience and connectivity should be preserved. In this paper, we describe such a service and analyze its impact on the network usage by means of a simulation.

Peer-to-Peer (P2P) file-sharing has become the killer application in the wired Internet and might also be highly attractive for mobile networks. In particular since UMTS operators are searching for new applications which do both: a) exploit the potential of the UMTS technology and b) motivate the user to adopt the new technology. In this work we are investigating the performance of an eDonkey-based mobile P2P file-sharing system by means of time-dynamic simulation. Mobile networks differ from wireline networks by the limited capacity of the radio link and the mobility of the users. P2P networks, in contrast, are overlays which consider the transport network in an abstract way. In a mobile environment, the question arises, whether the abstraction can be maintained and what will be the performance impact if there is any. We will show in detail how the mobile access technology (GPRS or UMTS), the churn behavior of mobile users, the file size of mobile specific content, and special infrastructure entities, such as a cache peer, influences the performance of the suggested mobile P2P file-sharing service.

Mobile networks differ from their wireline counterparts mainly by the high costs for air transmissions and by the mobility of the users. A new entity, denoted as the crawling peer, is suggested in order to optimize the resource mediation mechanism for a mobile P2P file sharing application. The crawling peer locates content on behalf of mobile peers. It is placed in the wireline part of the mobile network and thus, does not suffer from the above mentioned restrictions. The crawling peer is part of a comprehensive mobile P2P file sharing architecture [1] which is based on the popular eDonkey file sharing application. The performance of three querying strategies of the crawling peer is investigated with respect to banning at the index servers and the response time of requests, i.e. the time to find a file. The results show that the selection of an appropriate request strategy for the crawling peer maximizes the probability of locating a file while the probability to be banned by an eDonkey index server is minimized.

P2P file sharing is an interesting application in a mobile data network such as GSM/GPRS and UMTS. In particular in mobile environments, operation of P2P systems encounters several problems, such as a relatively narrow and expensive air interface, highly varying online-state (presence) of subscribers, hierarchical network structure, and limited device capabilities. The desire of operators is to add some value to P2P data flows and to turn them into services. At least some control over traffic and content should be possible, while preserving the basic P2P user experience and connectivity. Operation of P2P file sharing services in next generation mobile networks has to suit the needs of users as well as to accommodate the constraints imposed by 3G mobile technology and 3G network operation.